I haven't yanked a plug yet to see how my new carb setup is suiting the motor so I'm curious as to what size jets people find favorable for their 460.
I'm currently running #68 jets on the primary side of a Holley 600cfm. I don't know what the secondary plate flows. I'm more worried about the primaries since my foot's rarely in it.
And yeah I know - 600cfm is a little weak for a 460
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Assuming it's stock, 5500 rpm max and a good ignition/air cleaner/exhaust, I calc the cfm at....659.
Assuming this is all correct, I calc the fuel to be about 9% shy, I would increase the 68's 4.5% to 71's. If you were pulling over 5500 rpm I would then suggest changing out the venturi's to 650/700 cfm spec, but should work pretty well.
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I ran 72's in mine, but it had headers and a CompCams 268H. Pull a plug, itf they look good, leave it alone.
Alright so it sounds like I should be doing okay with the 68's. I'm still gonna yank a plug and see how she's burning.
Beechkid, the 600cfm is definetly not gonna cut it beyond 5000rpm but I have a steep 3.00 rearend gear plus the motor quits pulling hard after 4500rpm with the stock intake and exhaust.
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People work from sun to sun but a gearhead's work is never done. -An old mechanic's adage
I run a 4160 Holley 600 CFM on my 460 & I don't see anything weak about a 600 CFM. It depends what you are doing with it. Mine is for towing & the 600 CFM is perfect. I run #62 jets in mine. It came with 64s from Holley & I run in the 4000-5000 ft of elevation so I step DOWN 1 jet size per 2000 ft. Maybe that is why pulling a 10,000 # trailer I can get 7 MPG & 10-11 MPG empty. This is in an 86 F250 4x4. The engine has almost 190,000 miles on it. & has run this same set up for 40,000 miles.
I run a 4160 Holley 600 CFM on my 460 & I don't see anything weak about a 600 CFM. It depends what you are doing with it. Mine is for towing & the 600 CFM is perfect. I run #62 jets in mine. It came with 64s from Holley & I run in the 4000-5000 ft of elevation so I step DOWN 1 jet size per 2000 ft. Maybe that is why pulling a 10,000 # trailer I can get 7 MPG & 10-11 MPG empty. This is in an 86 F250 4x4. The engine has almost 190,000 miles on it. & has run this same set up for 40,000 miles.
WOW 62's!? I don't know what my elevation is here in MI, but it's definetly not as high as what you have to work with! It's good to hear that a 600cfm isn't getting skimpy though. I just find it hard to believe - the carb came off an '84 Mustang GT with a 302 in it and I put it on a 460 and don't need a jet change? WTF!
I'm not gonna complain about the carb though - it hauls x10 more ass with the Holley vs. the Motorcraft spreadbore!
I yanked a plug today to see what I'm working with. Looks lean to me - what do you think? Plugs are Boschs btw.
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People work from sun to sun but a gearhead's work is never done. -An old mechanic's adage
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- 600cfm is a little weak for a 460
